In comparison, tuition at the rest of the country's private school's increased by just 35 percent, Anderson and Ohm reported.

In the past 10 years, Ivy League colleges have only increased tuition 24 percent. All of the data has been adjusted for inflation.

Some of the most expensive schools in the city are Columbia Grammar and Preparatory ($38,340 for the 12th grade), Horace Mann ($37,275 for upper school), and Riverdale Country School ($40,450).

In the analysis, the reporters found that parents refrained from complaining, because they were afraid it would hurt their child's standing or hurt the chances of their younger children receiving admission into the school.

Several administrators told The New York Times tuition increases can be attributed to increase in teacher's salary, benefits cost increasing, and the maintaining of the expensive facilities that make the school so desirable to parents.